The RF (radio frequency) engineering of cellular, PCS (personal communications system) and other communications systems uses both predicted and measured system performance data. Predicted data is developed using known software tools or toolsets that model the RF properties of the communications system. Measured or test data is collected from either stationary equipment at one or more fixed sites (e.g., cell sites) within the coverage area or from portable or mobile test equipment that is driven about the coverage area while collecting system performance data. Certain system metrics are derived by processing the collected data.
Data collected by the portable equipment is referred to as “drive test data.” To conduct a drive test, one or more technician teams drive the coverage area while collecting measurement data using various known types of signal receiving and processing equipment. The collected and derived data can include, for example, S/N ratio, signal strength and bit error rate for each system channel, as well as GPS time and location. Those skilled in the art recognize that other data types may be collected or derived as determined by the nature of the communications system and operational difficulties that might be expected or have been observed during system operation.
Since there are multiple manufacturers of drive test data collection equipment and therefore multiple presentations of the collected data, a generic method for analyzing, checking, tabulating, combining, etc. the data, is desired. Post-processing tools are designed to perform these functions. Since the volume of the collected data is typically enormous (a single drive test about a coverage area may extend over several days), post processing should preferably also identify the most important data elements and segregate the collected data into subsets for easier display and analysis by the RF engineer responsible for system operation.
The collected data is stored or logged into files as collected. Early detection of problems with the drive test data is not possible, since currently available post-processing tools do not permit examination of the data for completeness and/or consistency until after the collection process is over. A drive test data collection problem may arise when an inexperienced drive team collects insufficient data or wrong data, or when the technician changes an equipment configuration during the collection process without corresponding modifications to the data collection equipment. Post-processing analysis may reveal such problems with the collected data, but they can be remedied only by collecting additional data during another drive test. Generally, it is not desired to conduct a second drive test after the first test has been completed due to the inconvenience and extra cost incurred.
Current post-processing tools also do not compare test data stored in different collection files. The results of such a comparison may be useful in identifying inconsistencies in the collected data or problems with the drive test collection equipment.